Where Does GEDCOM Come From?

Most genealogy software either uses GEDCOM files for its database or at least will allow the user to export data out to a GEDCOM file.

From the GEDCOM specification:

GEDCOM was developed by the Family History Department of The Church of Jesus Christ of Latter-day Saints (LDS Church) to provide a flexible, uniform format for exchanging computerized genealogical data. GEDCOM is an acronym for GEnealogical Data Communication.
Its purpose is to foster the sharing of genealogical information and the development of a wide range of inter-operable software products to assist genealogists, historians, and other researchers.

UncleGED does not produce GEDCOM files, nor does it modify the original GEDCOM file in any way.

In order to use UncleGED you will need to provide a GEDCOM file from another source. For example if you use FamilyTree Maker you can produce a GEDCOM file.

To export your Family File to GEDCOM using Family Tree Maker:

From the File menu, select Copy/Export Family File (ALT, F, C).

Click the Save as type drop-down list and select GEDCOM (*.GED).

In the File name field, type a name for the GEDCOM file. It must have the extension .GED.

In the Save in fields, select the drive and folder where you want to place your file.